Study of isotopic fractions and abundances of the neutron-capture elements in HD 175305

TL;DR

This study analyzes the isotopic fractions and elemental abundances in the metal-poor star HD 175305, revealing contributions from both s- and r-processes and indicating early s-process activity at low metallicity.

Contribution

It presents a parametric model fitting observed abundances and derives isotopic fractions, highlighting the early onset of s-process nucleosynthesis in metal-poor stars.

Findings

Combined s- and r-process contributions match observed abundances.

The isotopic fraction f 152+154 is approximately 0.582.

Early s-process activity detected at [Fe/H] = -1.6.

Abstract

The chemical abundances of metal-poor stars are excellent sources of information for setting new constraints on models of Galactic chemical evolution at low metallicities. In this paper we present an attempt to fit the elemental abundances observed in the bright, metal-poor giant HD 175305, and derive isotopic fractions using a parametric model. The observed abundances can be wellmatched by the combined contributions froms- and r-processmaterial. The component coefficients of the r- and s-processes are C1 = 3.220 and C3 = 1.134, respectively. The Smisotopic fraction in this star where the observed neutron-capture elements are produced is predicted to be f 152+154 =0.582,which suggests that, even though the r-process is predominantly responsible for the synthesis of the neutron-capture elements in the early Galaxy, the onset of the s-process had already occurred at this metallicity of [Fe/H] = -1.6.